Fluorescent lighting apparatus

ABSTRACT

The invention relates to an apparatus for identification of a concealed sign, such as a signature, on a card or the like and comprises a fluorescent member, a light source for stimulating the fluorescent member, a retaining member for holding the card carrying the concealed sign during the identification process and an infrared ray source. The apparatus of this invention may further include an optical system for directly comparing the visualize image of the concealed sign with a second sign and an instantly lighting circuit for the light source.

o I United States Patent 1 1 [111 3,794,882 Kitanosono Feb. 26, 1974[54] FLUORESCENT LIGHTING APPARATUS 2,996,617 8/1961 Heckscher 250/71 R2,901,653 8/1959 Gilmore 313/109 [76] Invent gfi ku 3,519,881 7 1970Engel et al 315 100 Tokyo, Japan Primary Examiner-James W. Lawrence [22]plied: July 1972 Assistant Examiner-Davis L. Willis [21] App} 270 20Attorney, Agent, or FirmFitzpatrick, Cella, Harper & Scinto Related US.Application Data [60] Division of Ser. No. ll9,6l3, March l, 1971, whichis a continuation of Ser. No. 735,823, June 10, 1968, [57] ABSTRACTabandoned.

1 The mventlon relates to an apparatus for ldenuficatlon 30 ForeignApplication priority Data of a concealed sign, such as a signature, on acard or June 12 1967 la an 4260067 the like and comprises a fluorescentmember, a light p source for stimulating the fluorescent member, a re-{52] U S Cl 315/100 250/461 taining member for holding the card carryingthe con- [511 6 39/04 cealed sign during the identification process andan [58] Fie'ld 71 5 infrared ray source. The apparatus of this invention5 5 may further include an optical system for directly comparing thevisualize image of the concealed sign [56] References Cited with asecond sign and an instantly lighting circuit for the light source.UNITED STATES PATENTS 3,166,998 1 1965 Watson 250/65 R 2 Claims, 23Drawing Figures PAIENIEDFEBZB'W 3794.882

SHEET 1 OF 6 I FIG. 1 FIG.2A Fl6.2B

Pmmw w 3,794,882

SHEEI 2 OF 6 iliii PATENIED H826 M4 sum 3 or 6 PAIENTED H5826 I974 SHEU5 0F 6 FIG. 14

PATENTED 4 3.794.882

SHEEI 5 [1F 6 1 FLUORESCENT LIGHTING APPARATUS RELATED CASES BACKGROUNDThis invention relates to a new apparatus for identifying concealedsigns or signatures and more particularly relates to an identifyingdevice utilizing the quenching effect of infrared rays on fluorescentmaterial.

Of late, the demand for the maintenance of secrecy in the handling ofinformations such as test data, specifications of machines and tools andsignatures and the transmission thereof has significantly increased. Forexample, in the banking industry, wherein the banks have several branchoffices in various parts of the country and withdrawals and checks maybe cashed at any number of these branch offices, there is a strongdemand for a means to identify the withdrawer or casher of the check.Moreover, with the advent of the credit card, an effective means foridentifying the party using the credit card has been intensively sought.

With reference to the banking business, in order to identify awithdrawer, there is presently nothing to depend upon except thesignature on the withdrawal slip or check. Accordingly, it is a simplemeasure for a malicious party to withdraw sums from a bank account orcash a check by simply imitating the signature on the note.

Therefore, various methods have been utilized to overcome theseproblems, such as issuing identification cards with the picture orfinger print of the authorized user thereon. However, even when thesecounter measures are employed, it is not always possible to obtaineffective protection for the depositor.

In accordance with an additional safe-guard, a concealed signatureorstamp of the depositor is placed on an identification card or withdrawalslip and same is given to the depositor. When the depositor wishes towithdraw money from the bank, he is requested to write his signaturevorto stamp his own stamp, and the written signature or stamp is comparedwith the concealed signature or withdrawal to confirm his identity.Thus, when an unauthorized user attempts a forgery; the signatures willnot agree and the withdrawl of the deposit can be rejected. When theabove system is employed, confirmation is easily accomplished and it ispossible to attain the effected protection for the depositor.

In accordance with one conventional method for concealing a signature,the original signature is deformed so that it can not be directly read.However, for this method, complicated optical systems and mechanisms arerequired for deforming the original, and, thereafter, a second system isnecessary for reading the deformed signature. As an example, it is knownto use fiber randon prisms to prepare a deformed image by modulating thearrangement ofthe image points of the normal image of the signature. Thethus concealed image is decoded by using a decoder having the same imagemodulating function. However, when such method is employed, two devicesare necessary, i.e., one for deforming the .signature and the other fordecoding the deformed image, and, therefore, the cost becomes high.Additionally, when the deformation of the signature is simple, amalicious party may easily decode the concealed sign by guessing at theclue for the deformation without using any specific decoder; but only bychanging the image arrangement of the deformed image. Therefore, thevarious contrivances for preparing a deformed image becomes complicatedand materially increases cost.

SUMMARY Briefly stated, our invention comprises an apparatus forconcealing a signature or the like wherein the signa ture is inked on acard which permits the passage therethrough of infrared rays. The inkwhich is used is of the type which blocks penetration of infrared rays.The surface of the paper having the signature is covered with an inkwhich visible light cannot penetrate, but infrared rays can.Alternatively, the surface may be covered with a thin film having asimilar properties with respect to ray transmission. In such-manner, thesignature of the stamp may be readily concealed.

The detection and identification of the signature thus concealed iscarried out by projecting an infrared ray pattern of the concealed imageon a fluorescent plate, the whole surface of which fluoresces, therebyquenching only the infrared pattern portions on the fluorescent plate toform a visible image of the concealed signature. The visible image maythen be compared with the signature of the party making the withdrawalby placing them adjacent each other or overlying one another. Inaddition fluorescing of the fluorescent plate in our device is effectedby stimulating the fluorescent plate with an ultraviolet ray sourcehaving an instant lighting circuit. In such manner, the identifyingoperation can be instantly carried out.

One type of conventional ultraviolet light employs a fluorescentdischarge tube having a filament circuit connected to a glow tube. Inthis system, however, when the glow tube and the fluorescent tube becomeOld, the lighting operation requires a considerable time. Similarly, inother conventional systems, the filament of the fluorescent tube ispreheated, or the fluorescent tube of the rapid start type is used, or astabilizer for rapid starting is employed along with the generallyemployed fluorescent tube to carry out quick lighting. However, theconventional systems suffer from the disadvantage of a filament which iseasily broken by the change of the lighting voltage and, therefore, thecost materially increases.

The fluorescent tube of the instant invention is free from theabove-mentioned drawbacks and provides instant lighting without causingahalf lighted state as in conventional systems. This is'accomplished byproviding non-linear elements such as varistors, connected in parallelwith the filament circuit.

Accordingly, it is an object of the present invention to provide a newapparatus for identifying and detecting a concealed image, such as asignature, by utilizing the quenching effect of fluorescent matter bymeans of infrared rays.

Another object of this invention is to provide an identifying apparatusthat does not require any special device for concealing a sign orpattern.

Other objects, characteristics and advantages of this invention will beclarified from the following detailed description wherein:

FIG. 1 is an aslant view of a card on which a sign or pattern isconcealed;

FIG. 2A is a diagram showing the concealing of a sign or pattern on apaper by coating the paper shown in FIG. 1 with an ink which prohibitsthe passage of light rays but passes infrared rays;

FIG. 2B is a diagram showing the concealing of a sign on the paper shownin FIG. 1 by sealing the same with a thin film;

FIG. 3 is an aslant view showing the arrangement of the elements of thedevice when identification is carried out;

FIG. 4 is a diagram showing one embodiment of the inveniton;

FIG. 5 is a diagram showing a second embodiment of the invention;

FIG. 6 is an aslant view of a complete apparatus according to thepresent invention;

FIG. 7 is a cross-sectional view taken across line lI of FIG. 6;

FIG. 8 is a vertical cross-sectional view taken across line Il-II ofFIG. 6;

FIG. 9 is a vertical cross-sectional view of a plate for attaching afluorescent plate according to the invention;

FIG. 10 is a vertical cross-sectional view of another embodiment of theplate for attaching the fluorescent plate;

FIG. 1 l is a partial cross-sectional view of the inven tion showing themanner of fitting the fluorescent plate to the apparatus of theinvention;

FIG. 12 is an enlarged partial vertical cross-sectional view of theswitch pin portion of this invention;

FIG. 13 is a view similar to FIG. 12 showing the switch pin in itssecond position;

FIG. 14 is a partial view of the printed base plate for the switch shownin FIGS. 12 and 13;

FIG. 15 is a circuit diagram of the apparatus of this invention;

FIG. 16 is a diagram showing the optical system of the device of thisinvention;

FIG. 17 is a partial view of this invention showing the base platewherein the card bearing the pattern to be identified is placed; 1

FIG. 18 shows a lighting circuit diagram of a conventional fluorescenttube;

FIG. 19 shows a lighting diagram of a conventional fluorescent tube;

FIG. 20 shows a lighting circuit diagram ofa conventional fluorescenttube;

FIG. 21 is a circuit diagram of the fluorescent tube to be applied tothe identifying device of this invention;

FIG. 22 is a graphical representation of the circuit of FIG. 21.

DESCRIPTION In accordance with the present invention, an original image2 of a signature or stamp is-written with an ink which blocks passage ofinfrared rays on a surface of a recording member 1. In general, writingpaper has low permeability for visible rays or ultraviolet rays, buthigh permeability for infrared rays. Also, an ink which is mainlycomposed of carbon black has a stron effect on the passage of infraredlight therethrough; as well as visible light. In accordance with theinvention, the original signature is placed on the recording member 1,

such as a card, and is obscured by smearing an ink 3 thereover. The inkpermits infrared rays to pass therethrough, but prohibits the passage ofvisible light so that the signature cannot be seen. As shown in FIG. 2B,the surface of the original image 2 may be sealed with a thin film 3having the same properties as the abovementioned ink, and in suchmanner, the original signature is concealed. With respect to thecovering of ink 3, any ink may be used which has oil black as the maincomponent. In cases where visible light can pass through the card orpaper 1 and the sign or pattern of the original image can be observed onthe back side of the paper, the back side is also coated with ink orsealed with a thin film.

In carrying out the identification of the concealed signature, the paper1 having the signature 2 in the concealed state is placed on afluorescent plate 4 as is shown in FIG. 3. An infrared ray source 5 anda filter 6, which passes only infrared rays are placed behind the paperI. On the opposite side of the paper I, there is placed an ultravioletray source 7 and a fluorescent plate 4. The infrared image of theconcealed sign is formed on the surface of a fluorescent plate 4 by theinfrared rays passing through the paper I. In other words, the portionsof the surface of the fluorescent plate 4 other than the portionscorresponding to the image of the concealed sign are quenched by theinfrared rays while the portions corresponding to the concealedsignature illuminate fluorescent light. In such manner, the concealedsignature is visualized and identification is possible. I

FIG. 4 illustrates the principle of the present invention as applied toan identifying device wherein the infrared light source 5, the infraredfilter plate 6, the fluorescent plate 4, and the ultraviolet lightsource 7 are arranged horizontally in that order. The filter plate 6 issupported at the lower portion there so that it can be tilted freely, asis shown by the dotted line. The card I bearing a concealed signature isplaced between the filter plate 6 and the fluorescent plate 4. Thefilter plate 6 is pressed against the card 1 so that the card 1 isclosely contacted to the fluorescent plate 4. Behind the fluorescentplate 4, a half mirror 9 is provided for reflecting the light comingfrom the fluorescent plate 4 upwards. Below the half mirror 9, there isprovided a base 10 whereon the card 11 bearing a second signature to becompared with the concealed signature is placed. A light source 12 isprovided on the upper side of the card 11 so as to illuminate same.

In the identification procedure, the fluorescent plate 4 is whollyilluminated by the irradiation of the ultraviolet light source 7provided behind the fluorescent plate 4. The fluorescent plate 4 is alsoilluminated through the card 1 bearing the concealed signature by theinfrared light source 5. Thus, the infrared rays which are not blockedby the ink of the concealed signature are projected on the fluorescentplate 4. As a result, the concealed signature 2 written on the card 1 isformed as a visible image on the fluorescent plate 4. This image isthereafter reflected by the half mirror 9 and can be observed by anoperator from the position 13. At the same time, a card 11 bearing thesignature to be identified is placed on base 10 within the sameview-field, thereby allowing for the comparison of the two signatures byparallelly placing or overlaying same.

FIG. 5 shows another principle of the apparatus of the invention,wherein the card 1 bearing a concealed signature is inserted between abase plate and an infrared ray filter 6. The filter 6 is rotated onshaft 8 to press and retain the card 1 between the base plate 15 and thefilter 6. An infrared ray lamp 5 is provided behind the infrared filter6 and at the same time an optical system composed of a lens 16 and anaslantly provided reflecting mirror 14 are provided behind the basemember 15 and positioned in such manner as to reflect the ultravioletimage on a fluorescent plate 4 provided with an ultraviolet light source7. A half mirror 9 for reflecting the light coming from the fluorescentplate 4 is aslantly provided in front thereof. Below the half mirror 9,a base 10 is positioned so that is is approximately the same distancefrom the half mirror 9 as the half mirror 9 is from the fluorescentplate 4. The card 11 bearing the signature to be identified is placedthereon and a light source 12 for illumination is positioned above same.

In the above-mentioned system the infrared ray pattern of the concealedsignature on paper 1 is transmitted through an optical system such asthe mirror 14 and the a 16 to the front surface of a fluorescent plate4, i.e., the side of the plate 4 which is stimulated and illuminated bythe ultraviolet ray lamp 7. In such manner, a quenched image of theconcealed sign is generated on the surface of a fluorescent plate 4.This image is observed on the half mirror 9 while the signature on cardll on the base 10 can be observed through the window sectionofhalfmirror 9, thereby providing an easy comparison. Therefore, inaccordance with this system, the infrared ray pattern and theilluminating surface of the fluorescent plate 4 are overlaid on the sameside to generate the quenching effect.

In the embodiment of FIG. 4, when the concealed image on card 1 ispressed-contacted between the infrared ray filter 6 and the fluorescentplate 4, the concealed image is inverted by the half mirror 9 and theopposite image can be observed by the operator at position 13. Thus,when identification is carried out, it is necessary to invert the card11 bearing the second signature to effect a correct comparison. On theother hand, in accordance with the embodiment shown in FIG. 5, theinfrafed ray pattern of the card 1 is inverted with the right side tothe left, and therefore in order to observe, the normal image, theinfrared ray pattern must be inverted and placed with the right side tothe left before entering lens 16.

Referring now to FIGS. 6 through 8, there is shown a unit encompassingour invention. The unit comprises a base portion having a box 17 whichencloses the electric circuit for lighting the infrared lamp and theultraviolet ray lamp described hereinafter. Located above the box 17, isa box 20 enclosing the detecting and identifying mechanism such as alamp, fluorescent plate, and an optical system. The box 17 of the baseportion and the box 20 are united toform the casing of the instantapparatus.

A rectangular opening 21 is provided at the top of box 20 and anoperating board 22 is mounted adjacent thereto so that it may be pushedinto the opening 21 from outside when identification is carried out. Ashaft pin 24 is provided on one end of the board 22 and ex- .tendsthrough the box 20, thereby providing a rotation point for the board 22.An L-type lever'25 is fixed on both side wall portions of the operation22, and pins 28 are provided on armplates 27 fixed on both sides of apressing plate 26. The pins 28 slidably engage a U- shaped retainer inthe lever 25. A retaining plate 29 for retaining the paper at apredetermined position by press-contacting the paper bearing theconcealed signature in parallel with the pressing plate 26 is alsoprovided, and the retaining plate 29 is provided with a guide pin 30 ateach of the corner portions thereof. (cf. FIG. 8). On the pressing plate26, there are provided holes at the portion corresponding to the guidepin 30 of the retaining plate 29, and the pins 30 on the retaining plate28 are respectively passed therethrough. At each pin 30, a spring 31 isprovided between the retaining plate 29 and the pressing plate 26. Theend portion of each pin 30 has a head 32 for preventing the guide pin 30fron being disconnected from the pressing plate 26 by the biasing ofreturn spring 31. (See FIGS. 7 and 8) As a result, the pressing plate 26and the retaining plate 29, are connected via pins 30 and return spring31.

In addition, the retaining plate 29 has an arm 33 mounted on bothsidewall portions thereof, such as by screws. At the other portionthereof, the arm 33 is rotatably supported by a shaft 33'. Accordingly,when the operation board 22 is pressed, it is pushed down in a clockwisedirection with the fulcrum 24 as the center. This, in turn, pushes thepressing plate 26 via the L- lever 25 fixed on the operating board 22and pin 28. As a result, the pressing plate 26 rotates the retainingplate 29 in a counter-clockwise direction with the shaft 33 as thefulcrum, while the return spring 31 is compressed.

A plate 34 for mounting the fluorescent plate 38 to 7 box 20 is providedon the front surface of the retaining plate 29. A document bearing theconcealed image is inserted between the retaining plate 29 and the fixedplate 34 through the slit 23 in the box 20. When the re taining plate 29is rotated in a counter-clockwise direction, the document is closelyretained.

Behind the pressing plate 26, an infrared ray lamp 35 is provided forirradiating the document bearing the concealed image. The pressing plate26 and the retaining plate 29 are provided with generally rectangularholes 26 and 29' for passing infrared rays'through the central portionsof the pressing plate and the retaining plate.

As shown in FIG. 8, the central portion of the retaining plate 29accommodates a glass plate 36. A plate 34 is mounted to the box 20 andhas an opening in the central portion thereof which corresponds with thewindows in pressing plate 26 and retaining plate 29. A metal frame 37for retaining a fluorescent member is inserted in the open area of plate34.

As is shown in FIG. 9, a fluorescen fluorescent 38, coated withfluorescent material 39, is placed on a glass plate 38, and a thin film49, such as Mylar, is used to cover the plate 38. The thin film is fixedwith a retainer 41 to hold the fluorescent plate 38 onto the metal frame37. In an alternative method, as shown in FIG. 10, a fibrous layer 40'is used as a face plate instead of the thin film of Mylar."

Referring again to FIG. 8, an ultraviolet light source 42 is provided onthe front side of the fixing plate 34 which illuminates the surface ofthe fluorescent plate 38. The fixed plate 34 is mounted on the box 20 insuch manner that the fluorescent plate 38 fixed on the central portionthereof and the glass plate 36 inserted onto the retaining plate 29, areall positioned in agreement.

In order to light the ultraviolet light source 42, and infrared lamp 35,a switch pin 50 is provided which passes through a hole 43 in theretaining plate 29 and fixing plate 34. The switch pin 50 also passesthrough a hole provided in the card 1 bearing the concealed sign and,therefore, will not operate the respective lights unless the hole in thecard is at such position.

A lamp 44 for illuminating the matter bearing the second signature to beidentified is provided at the front portion of the plate 34 for fixingthe fluorescent plate. The lamp 44 is provided with a hood 45 whichdirects the light of the lamp toward the base 19. Thus, the matterbearing the signature to be identified is fully illuminated when it isplaced on the base 19. A glass plate 46 is mounted into a window at thebottom of box for observing the matter bearing the signature to beidentified.

Referring now to FIG. 11, the switch pin 50 is provided with a washer 51at one end thereof and is moveably inserted into a small hole providedat the lower portion of the window 26' in pressing plate 26. A skirtwasher 53 is made of an electroconductive material and is in contactwith pin 50 at the central portion thereof where it abuts an annularprojection provided on the pin 50. A coil spring 52 is provided betweenthe washer 53 and the pressing plate 26, and the switch pin 50 is biasedthereby towards holes 54 and 43 provided in the fixing plate 34 and theretaining plate 29, respectively.

A printed base plate 58 is adhered to the retaining plate 29 andprovides contacts 56 and 57, as is shown in FIG. 14. The switch pin 50is allowed to enter hole 43 of the fixing plate 34 through a holeprovided at a predetermined position in the card bearing the concealedsignature. In such manner, the conductive washer 53 provided on the pin'50 contacts the two electrodes 56 and 57, thereby completing anelectrical circuit.

FIGS. 12 and 13 show enlarged views of the switch pin 50 of FIG. 11. InFIG. 12, the card 55 bearing a concealed signature is not provided witha hole at the same position as that of the switch pin 50, and in thiscase, the switch pin 50 cannot enter hole 43 of the fixing plate 34.Therefore, the conductive washer cannot contact the electrodes 56 and 57of the printed base plate 58 and the electrode source switch of theinfrared and ultraviolet light sources cannot be turned on. However, inFIG. 13, the card 55 is provided with a hole in the position of theswitch pin. In this case, the switch pin 50 enters into the hole 43 andthe conductive washer contacts the electrodes 56 and 57, therebycompleting the electric circuit and illuminating the respective lights.

FIG. 15 is a circuit diagram of the embodiment described above, wherein:plug P is connected to an AC outlet; PL is a pilot lamp, S, is the mainswitch; FM is a fan motor for cooling; S is a switch comprising aconductive washer 53 provided on the switch pin 50 and the electrodes 56and 57 on the printed base plate; Rel, is a relay which is operated whenthe switch S is turned on, and has movable contacts a, through a,; L andL are the lamps for illuminating the matter to be identified and areserially connected to a variable resistor VR, for regulating thebrightness. An infrared ray lamp L, is provided behind the pressingplate 26, and

is serially connected to the movable contact of the relay Rel, and theresistor VR, for regulating the amount of irradiation.

Fluorescent tubes FL, and FL, are connected in series to the moveablecontacts a, and a of the relay Rel, which are respectively connected tothe circuit connecting the filaments of the light source. The contactsa, and a are normally closed and are, therefore, the contacts fordischarging thermoelectrons within the respective tubes. For preventingnoise, we provide capacitors c, and 0 Thus, the respective lamps areserially connected to the movable contacts a, a, of the relay Rel,.Therefore, when the switch S is closed and the relay Rel, is operated,contacts a, and a, are in the off state and a high voltage is appliedbetween the two filaments of the fluorescent tubes and the respectivelamps are lighted.

Accordingly, when the hole punched through the card 1 bearing theconcealed signature and the position of the switch pin 50 arein'agreement, the switch pin enters the hole 43 provided in the fixingplate 34. and the electroconductive washer 53 contacts the electrodes 56and 57, thereby completing the circuit, i.e., the switch S is turned toan on condition, and as a result, the relay Rel, is operated and themovable contacts a, and a of the relay are turned to an off conditionand contacts a and a, are turned to an on condition. In such manner, therespective lamps are turned on simultaneously.

FIG. 16 depicts the optical system of our invention, wherein the numeral36 is the pressing plate which is inserted into the retaining plate 29.The retaining plate 29 is overlaid with the fluorescent plate 38provided on the fixing plate. For the sake of convenience, in thisfigure, the two plates 36 and 38 are shown in intimate contact, butactually, between the two plates, the card bearing the concealedsignature is inserted.

A reflecting mirror 47 is provided for inverting the quenched imageformed on the fluorescent plate 38. A second reflecting mirror 48 ispositioned to direct the inverted image which is reversed by thereflecting mirror 47 to the eyes 59 of the viewer. Additionally, themirror 48 inverts the image so that it is seen in its correct position.The aslantly provided reflecting mirror 48 is a half mirror, i.e., onlyhalf the mirror reflects, which leads the quenched image to the eyes ofthe operator and through which the operator can see the image of thematter bearing the signature to be identified, which is placed on base19. A magnifying glass 49 is placed in the viewing aperture. Between thebase 19, and the optical system, a glass plate 46 is stationed for Ipreventing dust from entering the optical system.

The distance between the half mirror 48 and the base 19 is adjusted tobe equal to the sum of the distance between the half mirror 48 and thereflecting mirror 47 and the distance between the reflecting mirror 47and the fluorescent plate 38. Therefore, the quenched image on thefluorescent plate is reflected by the refleeting mirror 47 and the halfmirror 48 and is viewed by the operator with the virtual image thereofformed on base 19.

As shown in FIG. 17, the base 19 is connected to an adjusting screw 60and the base portion thereof is freely inserted into the hole 62provided on the base plate 61 of the box 17. The base portion of thescrew 60 has a washer, and when the adjusting screw 60 is rotated, thebase is moved horizontally in the direction shown by the arrow. Thus,the adjustment of the base 19 and the half mirror 48 in a lengthwisedirection of the light path can be carried out.

Having described the basic components of our invention, a briefexplanation of its manner of operation will now be given. When a persondesired to cash for example, a check, the check bearing his signature isplaced on the base 19 and an identification card bearing his signaturein a concealed state is inserted into the slot 23 of the box 20clockwise direction the retaining plate 29 and the fixing plate 34. Theoperation plate 22 is then rotated in a lockwise drection on the shaft24, and the pressing plate 26 is rotated in a counter-clockwisedirection through the pin 28 and the L-shaped lever 25. When thepressing plate 26 is rotated, it compresses the springs 31 and theretaining plate 29 is pushed by spring 31 provided on the guide pin 30and is rotated in the counter-clockwise direction with the shaft 33' asthe fulcrum. Thus, the card 55 is closely held between the pressingglass plate 36 of the retaining plate 29 and the fluorescent plate ofthe fixing plate 34 (see FIG. 11). The card 55 has a punched hole at apredetermined position at the lower portion therefor, and when thepunched hole agrees with the position of the switch pin 50, the switchpin 50 is introduced into the hole 43 in the fixing plate 34 and theelectroconductive washer provided on said pin contacts the electrodes 56and 57.

This, in turn, activates the infrared ray lamp 35, the ultraviolet raylamp 42 and the illuminating lamp 44 within the box 20.

When the ultraviolet lamps 42 provided on the upper and lower sideportions of the fluorescent plate 58 are lighted, the fluorescent layercoated on the fluorescent plate is stimulated and illuminated. When theinfrared lamp 35 is lighted, the infrared ray pattern of the concealedsignature is irradiated onto the fluorescent plate, and the quenchingeffect is generated, resulting in a quenched image formed on thefluorescent plate. This image is readily observed by the operator as thenormal image through the reflecting mirror 47 and the half mirror 48. Atthe same time, the signature to be identified, placed on base 19, can beobserved through the transparent half of mirror 48. Thus, theidentification can be readily carried out by arranging the two images tocoincide.

I In connectionwith our identifying device, we have also found a newmanner in which to activate a fluorescent lamp so that it lightsinstantaneously. There are numerous conventional fluorescent lightingcircuits such as shown in FIG. 18, wherein a fluorescent tube 101 havingfilaments 102a and 102b are in circuit with an A.C. power source 106through a stabilizer 103, re-

I sistor 107 and switch 105. In this conventional lamp system, theswitch 105 is closed in order to light the fluorescent tube 101. In suchmanner, the filament circuit is closed to pass a heating current throughthe filaments 102a and l02b so that thermoelectrons are dischargedtherefrom. Whenthe switch 105 is released, the voltage between the twofilaments 102a and l02b is abruptly raised and a discharge is startedbetween the two filaments, thereby lighting the fluorescent tube. Thedrawback in this system is that it is necessary for the filament circuitto be closed until thermoelectrons are discharged and, therefore, it isnot possible to instantly light the tube.

In another conventional lighting circuit, as shown in FIG. 19, a glowstarter 108 is connected to the lighting circuit. In this circuit, thecontact of the glow starter is closed at first and, therefore, a heatingcurrent passes through the filaments 102a and 102b, causingthermoelectron discharge. After a predetermined time, the contact of theglow starter is opened, and voltage is applied between the filaments102a and 102b, thereby lighting the tube. In this case, instant lightingis still not available.

To negate the aforementioned drawback, it is also known to carry out theabove lighting operation in opposite manner. Namely, as is shown in FIG.18, the switch 105 is normally kept closed and current is always passedthrough the fllament circuit to preheat the filaments 102a and 102b. Tolight the tube, the switch 105 is opened to apply voltage between thetwo filaments. However, in such case, when the voltage of the powersource 106 is lowered, the resistor 107 must have lower resistivitysince it is necessary to preheat the filaments sufficiently to dischargethermoelectrons from the filaments 102a and 102b. When the voltage ofthe electric source 106 is raised, the filaments 102a and 102b becomeoverheated and the discharge caused by releasing thermoelectrons occursat both ends of the fluorescent tube, thereby causing a half-lighted orslightly lighted state. On the other hand, when the resistivity of theresistor 107 is increased against the elevation of the power source 106,and when the voltage of the power source 106 drops, the filament currentbecomes so small that lighting becomes increasingly difficult.

As a further example of a conventional lighting circuit, there are thosesystems where fluorescent tubes are of the rapid start type. In thisarrangement, a stabilizer is utilized, as shown in FIG. 20. In suchcase, the stabilizer 111 is connected between the two filaments 110. Aheating current is passed through the two filaments 110 by means of thestabilizer 111 after closing the switch 112. At the same time, theelevating voltage of the A.C. power source 113 is also applied to thetwo filaments 110. Therefore, the fluorescent tube can be lightedinstantly through the discharge in the tube 109 caused by the closing ofthe switch 112. However, in this case, the stabilizer must be of thetype which can carry out the quick elevation of voltage, and such astabilizer is rather expensive. Accordingly, this arrangement isimpractical for a low cost unit.

Referring now to FIG. 21, there is shown the lighting circuit of ourinvention which comprises: an ultraviolet light source 101; filaments102a and 102b; a stabilizer 103, and an A.C. power source 106. Thefilament 1020 is connected to the electric source 106 through thestabilizer 103, and at the same time, a varistor 114, as an elementhaving non-straight line property, is connected to the terminals of thefilament. A second varistor 114 is connected to the filament terminalsof the filament 102b, and one of the terminals of each filament is con-.

nected to the switch 115 which is normally closed and is opened onlywhen the lamps are lighted. Since the switch 115 is normally closed, anelectric current normally passes through the two filaments 102a and l02bto heat same and discharge thermoelectrons. However, as shown in FIG.22, the varistor 114 connected to the two filaments is of the type thatwhen the voltage applied to the varistor is smaller than the lightingvoltage V0 of the fluorescent lamp, current hardly flows through thevaristor. However, when it becomes larger than V0, the varistor abruptlystarts to pass the current.

Therefore, when the voltage of the lighting electric source 106a of FIG.21 is low, i.e., when the voltage of the lighting electric source islower than the lighting voltage V0. current barely passes through thevaristor 114, and most of the current passes through the filaments 102aand 102b. On the other hand, when the voltage of the power source 106 israised higher than V0, the current passing through the filaments 102aand l02b is increased along with the increase of the voltage of thepower source, but the current passing through the filaments 102a and102b becomes constant because the current passing through the by-passshunting from the varistor 1 14 is abruptly increased. Thus, even if thevoltage of the power source 106 is changed, the current passing throughthe filaments 102a and 102b is kept constant when it is in theneighborhood of the lighting voltage V0. When the lighting switch 115 isopened, the voltage of the power source is directly applied between thetwo filaments and a discharge is started between the two filaments tolight the lamps instantly. In this circuit, the current passing throughthe two filaments is kept constant by the varistor 1 14 against thechanges of the alternating current voltage and, therefore, it ispossible to obtain the desirable instant lighting circuit.

In the above embodiment, a varistor is used as the filamentcurrent-controlling element. However, any

other element having the non-straight line property as that of avaristor can also be used.

Thus, in applying the above circuit and elements to the identifyingdevice of this invention, when the switch pin 50 contacts electrodes 56and 57, the ultraviolet light source, as well as the infrared light andilluminating lamp are instantly turned on, thereby permitting quickcomparison of the two signatures.

What is claimed is:

l. A fluorescent lighting apparatus comprising a fluorescent lamp havinga pair of opposed filaments, and a lighting circuit for said lamp, saidlighting circuit including an electric source circuit connected to applya voltage to one terminal of each of the filaments of said lamp to causedischarge between said filaments, a filament preheating circuitinterconnecting the other terminals of said filaments and having aswitch which is closed during preheating and which is opened to lightsaid lamp, and a filament current controlling circuit connected acrossthe two terminals of at least one filament of said lamp, saidcontrolling circuit including a non-linear element.

2. A fluorescent lighting apparatus according to claim 1, wherein saidnon-linear element is a varister.

y I Uh 'rsnsu rrs PATENT O FICE CERTIFICATE OF C'QRRFCTKON Patent No. 3794 8 2- Dated February 26 1974 I v 5') TAfrsUsHI 'KI'TANOSONO It iscertified that error'appears in the above-identified patent and, thatsaid Letters Patent arehereby corrected as shown below:

Before "Filed; Ju-ly l0,-l972" insert -A ssignee CAlfIGN KABUSHIKIKAISHA, Tokyo, Japan---;

In the Abstract, line 9, "Lvisualize" should read -visualized-- Column3, line 14, "inveniton" should read -invention'; Column 3, line 65,"stron" should read strong- Column 4 line 38, "there" should read thereof--;

Column 5, line 24, "a 16" should read -lens l6-- Column 5, line67,.after "operation". insert -board-;' Column 6, line 55, delete"fluorescen";

Column 6, line 55, after "fluorescent" insert -plate; Column 7, line 48,"electrode" should read ele,ctrio- Column 7, line 58, should read 7Column 9, line 6, "desired" should read -desi res--;

Column 9, line 10 after "box 20" delete "clockwise direction" and insert-and between- Column 9;, line 12, "lockwise drection" should read-clockwise.direction-;

Column 11, line 4,- after "V0" should read Column 12, line 25,"varister" should read -varistof- Signed and sealed this 17th day ofSeptember 1974.

( EAL) Attest:

MCCOY M. GIBSON JR. c. MARSHALL DANN Attesting' Officer I Commissionerof Patents

1. A fluorescent lighting apparatus comprising a fluorescent lamp havinga pair of opposed filaments, and a lighting circuit for said lamp, saidlighting circuit including an electric source circuit connected to applya voltage to one terminal of each of the filaments of said lamp to causedischarge between said filaments, a filament preheating circuitinterconnecting the other terminals of said filaments and having aswitch which is closed during preheating and which is opened to lightsaid lamp, and a filament current controlling circuit connected acrossthe two terminals of at least one filament of said lamp, saidcontrolling circuit including a non-linear element.
 2. A fluorescentlighting apparatus according to claim 1, wherein said non-linear elementis a varister.